Rotor construction.



B. A. BEHREND.

Y ROTOR GONSTRUGTION.

APPLIOATION FILED nr.o. 1,1905.

932,097. Patented Aug. 24, 1909.

Z SHEE'IS-SEEET 1.

Wmvassas UNITED STATES PATENT OFFICE.

BERNARLD ARTHUR BEI-IREND, OF NORWOOD, OHIO, ASSIGNOR T0 ALLIS-GHALMERS COMPANY,

A CORPORATION OF NEW JERSEY, AND 'IHE BULLOGK ELECTRIC DIANUFACTURING- CO A CORPORA'IION OF OI-IIO.

ROTOR CONSTRUC'I ION.

Specification of Letters Patent.

Application filed December 1, 1905. Serial N0. 289,743.

T0 all w7wm il3 may concem:

Be it known tha't I, BERNARD ARTHUR BEHREND, oitizen of the United States, residing ut Norwood, in the county 0f Han1ilt0n und State of Ohio, have inventecl certain new and usefnl -Improvennents in Rotor Consftrnction, of which the following is a full, clear, und exactspecification.

My invention relates to the rotary field me1nbers of dynam ,gelectric machines and particularly to the construction 0f field 1nembers 0f high speed turbo-genemtors.

The rotzuy field members 0f turbo:alter nators, 011 aocount of the exceeclingly high speeds t0 which they 2ue subjeoted, mus be Well balanced anc1 sufilciently strong t0 resist enor1nous centrifugal forces; the o0re zmd pole pieces should be so constructed that the rot-ary menlber Will have a sn1ooth exterior to avoid the noise and air resistance which would otherwise result, the field poles a-nd coils should be so construeted and arranged, that the latter will not be disarranged nor displaced at -the highest speeds; und also the core should be so construeted that the core ancl coils Will be ventilated und that sufficient air currents Will be forced througn the stator t0 prevent an undesirable er dangerous rise of temperature therein.

A rotary field member possessing most 0f the above requirements is shown in U. S. Patent N0. 780,085 granted Jan. 17, 1905 t0 W. D. Pomeroy and myself. The rotor, shown in this patent, is cylindrical in form and has a smooth exterior. Thus the disagreeable noise und. air resistance is lessened, since there are no prominent pole pieces 1101 projections 0f any kind on its outer eylindrical surfaee. The core is provided Wi1;h radial slots in which the concentric field coi1s are 1ocated. In this machine, the core is built up 0f groups of lan1inae spaced apart, so es 130 fo1m ventilat-ing s1ots o1 passageways. The laminee are provided with a number of holes or perforations, whieh, when the lan1inae are assembled, ahne, forming axial air passageways, which co1n municate with the spaces between ehe groups of laminze, and extend fron1 enc1 to end 0f the core. WVhen the field men1ber is rotated in operation, air is drawn from the ends of t-he n1achine th1ough the axial passageways and is forced out-ward through the passageways between the groups of laminee, and is forced over the face of, a'nd through the core 0I" the stator. In the strneture shown in this patent, the lznninm are nmde from thin sheet n1etal. 1t is therefore necessary that, between contiguous groups of Ianninze, st1ong spaeing 1nen1bers be employed entirely around Ehe core, to hold the gronps apart. It has been found that in large machines (lesigned f01 very high cu1rent-s and high V01- tage that these spacing me1nbers between ehe groups of l-a1ninee interfere seriously with ;he Ventilation 01: the machine. It is theref0l' desirable t0 so construct the machine thatthese spacing members can be dispe1ised -.vit-h. Furthern1ore, the field member of large machines designed for several thou- Sand kilowatts, n1nst be large in diameter'.

It is not expedient for several reasons to provide eircular steel punchings having a dinmeter greater than a eertain length, one of the 1eas0ns being the great cost in providing large expensive dies and the difliculty anc1 expense in obtaining sheet metal of suf ficient size. Therefore, in laminated rocary field me1nbers having a diameter say 0f foul feet 01 more, it wonld be necessary to build 1115 the core of seg1nents. It W111 be easily nnderstood, ahnt such a struoture built up 0f -a multiplieit-y of parts would be undesirable f0r the reason that itwould not possess the necessary strength and rigidity required f01 the great peripheral speeds for which the str'ucture is intended.

One 0f the objects 0f my invention is t0 so construct the rotary 1nember thatthe la1ge nu1nber oft spacing bloeks in the passageways of the core ean be dispensed with, so that both the rotary field and the stationary a1- matnre Will be well cooled by the fan-like action 0f the formen A fur'ther object of 1ny invention is t0 provide a core structure 1"0r large high speed rotary field members having the general design 015 the rocor shown in the patent referred fo which W111 be sufficiently strong and compact t0 resist the centrifugal forces at any speeds to Which the roter may be subjected.

W'ith these ends in view, 1 employ instead of groups 01 laminze, strong rigid, solid steel disks, a definite number 0f wh'ich a1e arranged side by side on the shaft. These disks are so construoted and arranged that a ventilating space is provided between each pai1 of acljacent disks. The disks a1e Suffieiently streng to withstand great centrif1r MPANY Patented Aug. 24, 1909.

gal stresses and have suflicient inherent stifl ness and rigidity that few if any spacing members are required, whereby there Will be an unobstructed circnlation 0f air. The disks are provided with radial slots in which are placed the field coils formed preferably 01 edgewise wound strap c0pper and having inclined 0r radial sides and parallel ends.

1v1y invention consists in the details of eonsiruction and combinations of elements described in the specification and set forth in the appended claims.

F01 a better understanding of my inventi0n, reference is had to the accompanying drawing, in which,

Figure 1 is an elevat-ion 0f a rot0r, parts being broken away for the sake of clearness; Fig. 2 is a sectional view 0f my improved rotor eore, the section being taken through the e0re disks approximately along the ]ine 22 of Fig. 3; hig. 3 is an elevation 0f one 01' the c0re disks; and Fig. 1 is an edge Vie W 0I the same, with one 0f the rotor coils shown in section.

As my invention relates t0 the rotor only of a turbogenerator I have not considered it necessary t0 illustrate the stator. The core 0f the rotor is mounted 0n a shaft 10. This c0re is cylindrical in shape and has a comparatively sn1ooth exterior and therefore the humming noise, and great frietional resistance ineident t0 high speed rot0rs, are reduced t0 a minimum. It has been proposed t0 build up the core 0f punehed laminaz, Whi0h are arranged in groups spaced apart by venti1ating spacing disks. 'lhis construction is satisfaetory under sonne conditions, especially i0r maclnnes designed for such loads and speeds that a rot0r of comparavely small diameter can be employed. In large machines, h0wever, the peripheral speed is so great that the lanninated strueture, espeeially if the laminae are segmental instead 0f circular, may n0t possess the requisite strength to resist the centrifugal stresses, and furthermore the necessary spacing blocks between the groups of laminae obst-ruct 130 a great extent the free circulation 015 air through the ventilating passageways in the rotor and stator. T0 av0id these difficulties and 130 improve in general the design of the rotary field member, I employ for the core, instead of the laminated units, heavy, rigid steel disks 11, of a thickness equal approximately to the thickness 01: a group of lannnae..v

The thickness of the disks may be varied to suit the circumstances 0f each case. These disks are arranged side by side and as many are employed as is necessary t0 obtain the necessary length of core.

Each disk 0r core-unit is made from a circular plate o1 disk 016 steel, Whieh is provided with a hole 12 130 receive the shaft, and one 0r more keyways o1 keyslot-s 18. The disk is carefully machined 0n all sides and turned to the proper diametesr. An integral -rim 0r flange 14: is preferaloly provided around the opening 12, on one side 0f each disk, in order that ventilating passageways 15 1nay be provided between the assembled disks. Groups of radial slots 16 are milled a sufiicient distance int0 the body of each disk, the number of radial slots depending 011 the nu1nber'of poles and the number of concent-ric coils per pole. Referring t0 Fig. 3, it is seen tha twenty-four slots are provided, six in each group, the disk illustrated being intended for a four-pole rotor, having three concentrie coils per p0le. Between each pair of slots 16 are teeth 17 and bet-ween the groups 0f sl0ts are comparatively large unslott-ed ole faces 18. 'Iransverse ventilating openings 0r passageways 19 and 20 are provided in each disk adjacent the flange 14. The openings 19 which= are larger than the opening 20, are located opposite the p0le faces, while the smaller openings 20 are 10- eated opposite the groups 015 sl0ts 16. The disks ar"e preferably provided with holt holes 21, and as shown in I*ig. 2 one side of each of the disks, except the outer disk at the left side 0f the fiqure is provided with recesses 22 about the holt holes 21. The purpose f' these recesses Will appear later. The slots 16 are preferably milled, and the ventilating openings are prei'erably drilled, in each disk separately. Slots 23 are milled in the outer en-d and 0n each side of each tooth for the reception 015 brass '0r bronze coil holding wedges. These slots are preferably milled in all the disks at the same time.

The disks are assembled 0ne at a time on the shaft and are held tightly together by end members 21 and holding nnts 25 screw threaded on the shaft. Although I prefer to use bolts t0 assist in drawing the disks tightly together, I do n0t c0nsider this absolutely necessary. Tie bolts 26, one of which is shown in I ig. 2 pass thr0ugh the holes 21 in all the disks. 'Ihe outer disks 11 and 11 are provided with recesses 27 for the reception of nuts 28, 0n the ends 0f the b0ls 26. Separating washers 29 which surround the bolts 26, are seated in the recesses 22 011 the disks and hold the outer portions 0f the disks firmly together. 1 d0 not consider the use of the washers 29 as necessary, but prefer 130 employ the same as they interfere only t0 a slight extent t0 the circnlation 0f air between the disks. It is seen that the flange 14 on the one sicle 0f each of the disks 11 and 11 rests against the unflanged or smooth side of the adjacent disk. I do not wish t0 be confined t0 the use of flanges integral with the disks as separate spacing rings may be employed if desired. I preier however to employ the structure shown as it is desirablet0 reduce as much as possible the number 0f parts 0n the roter. By means 0f keys which engage the slots 13 and the corre- Sp0nding sl0ts 011 tl1e shaft, tl1e disks are prevented fro1n turning relative t0 t-l1e sl1aft and by means of tl1e nuts 25 and bolts 26 tl1ey are held tigl1tly togetl1er. The holes 19 and 20 in the several disks aline when tl1e latter are assen1bled and eom1nunicate Witl1 tl1e spaces between tl1e disks.

Goncentric c0ils 30 are plaeed in the slots. These coils are preferably for1ned fr01n strap copper edgewise wound and each coil l1as inelined sides, Wl1i0l1 are radial witl1 respect t0 tl1e axis, and parallel ends. As is clearly shown in Fig. l, tl1ere are t-l1ree coils per p0le, 011e 0f tl1ese c0ils being shown in Fig. 3 in transverse section.

Tl1e radial sides 0f tl1e c0ils are held in place in tne slots by brass 0r bronze wedges 31, whicl1 are seated in tl1e notches 23 in tl1e outer ende or" tl1e teetl1, and tl1e parallel ende 0r end-turns 32, whieh prc-jeet bey0nd the c0re are surrounded by rigid steel rings 33 Whicl1 prevent tl1e displacement 0f tl1e ends of tl1e c0ils by centrifugal aetion, said rings fitting in tl1e gr0oves 3% provided in the disks 11 and 11".

Brass 0r steel end rings 0r plates 35 are bolted t0 the end rings 33 and to extensions 36 0f end members 24:. These plates proteet tl1e end turns. Tl1e end members are provided Witl1 circular air passageways 37 Wl1iel1 aline witl1 tl1e axial passageways 0f tl1e core. I l1ave sh0wn 110 supports for tl1e end-tnrns 0f the c0ils between the latter and tl1e extensions 36 0f tl1e end members 24. If desired such supports may be employed.

Vl1ile I l1ave shown a specific embodiment- 0f 1ny invent-ion, I do not wisl1 t0 be comfined t0 tl1e sa1ne, as many minor changes may be made witl1out atlecting the 111ai11 features 0f 1ny invention, and I ai1n in n1y clain1s to cover all tl1e changes and modifications Wl1icl1 d0 not involve a departure 1"r01n tlie spirit and sc0pe 01?" my invention.

Reference is l1ere 111ade t0 111y c0-pending applieation Serial N0. 225,072, filed Sept. 19, 190l f0r clain1s covering generically tl1e specific invention 0t' this applieation.

\Vl1at I clairn as new and desire t0 secure by Letters Patent is l. In a r0tary field member, a shaft, a plurality 0f ri id circular steel disks mounted side by side 011 said sl1aft, eacl1 of said dislrs l1aving a definite predetermined tl1ickness, and heilig provided with radial 1nilled sl0ts arranged in groups for1ning wedge sl1aped p0le pieces, witl1 a plurality of transverse rentilating openings adjacent tl1e sl1aft, witl1 a plnralit; 0f holt l10les near tl1e peripl1ery 0f tl1e disk, and with an integral flange between tl1e sl1aft and tl1e transverse ve11tilating l10les,- tightening nuts 0n tl1e sl1aft f0r forcing tl1e flange of eacl1 disk in engage1nent with tl1e next adjacent disk, tie holte passing transversely tl1rougl1 tl1e disks near tl1e outer peripl1ery, spacing wasl1ers 0n tl1e bolts between adjacent disks, and wedge sl1aped field coils ot edgewise W01111Cl strap copper in tl1e slots, tl1e whole structure having a s11100tl1 exterior.

2. In a rotary field 111e11111e1, a shatt, a c0re c0n1prising a plurality ot' rigid, circular, .steel dislis 0t definite thickness 11101111ted side by side 011 tl1e sl1aft in auch a 111a1111er tl1at tl1ere are ventilating spaces letween adja cent dislrs, eacl1 of eaid disks being provided Witi1 groups 0f open radial el0ts and pole pieces between adjacent groups, wedge sl1aped field c0ils 0f edgewise wound strap copper located in said suots, there being a number 0f concentric c0ils per p0le, said c0ils l1a *ing radial sides, and 3arallel ende Wl1lCll are l0cated beyond tl1e ende 0f tl1e core, rigid rings 01 banale surrounding tl1e projecting portions 0f tl1e coils, end members at tl1e ende 0f tl1e core and bearing against tl1e two outern1ost disks, and eircular plates 01 disks seeured t0 the rings and 130 said end 1ne1nbers so as t0 protect tl1e ends of tl1e coils.

3. In a rotary field 111e111be1 0f a dynamoeleetric machine, a sl1aft, a e0re comprising a plurality 01? rigid circular steel disks 0t' definite tl1ickness, loeated side by side 0n tl1e sl1aft, said disks l1aving radial slots and wedge slraped pole pieees, and a plurality o;t wedge sl1aped field coils l0cated in tl1e slots, said c0ils being f0r1ned 0f edgewise wound strap copper and l1aving radial 0r outwardly diverging sides and parallel ends.

4c. In a r0tary field member of a dynan1oelectric macl1ine, a shaft, a core comprising a plurality 0f rigid cireular steel disks 0f definite thickness, located side by side 011 tl1e sl1aft, said disks l1aving radial sl0ts and Wedge shaped p0le pieces, and groups 0f 0011- centrically arranged wedge sl1aped field c0ils 0t edgewise wound strap copper in tl1e slots, said c0ils l1aving radial sides and parallel ende.

In a rotary field 111e111ber 0f a dynamo electric 1nacl1ine, a slraft, a eore comprising a plurality 0f rigid cireular disks 0f definite thickness located 011 said sl1aft, said disks l1aving radial sl0ts and wedge-shaped pole pieces, and a coil 0f edgewise wound strap copper surrounding each 0I" said wedgesl1aped pole pieces, said coil l1aving radial sides and parallel ende.

(S. In a rotary field 111e111be1 0f a dy11a1110 eleetric machine, a sl1aft, a core co1npriSing a plnrality 0f rigid circular disks, niounted 011 tl1e shaft and spaced apart so as t0 forn1 ventilating passageways, said disks l1aving radial sl0ts and wedge-shaped p0le pieces, and field c0ils 0f edgewise vs0und strap sopper l0eated in said slots and surrounding said pole pieees eacl1 ot Said coils having radial sides and parallel ends.

7. In a rotary field me1nber ot a dynamo electric machine, a shaft, a core comprising a plurality of rigid circular steel disks, saicl disks having radial slots ancl wedgeslmped pole pieces, fielcl coils 0f eclgewise wouncl strap copper ancl having radial sicles anal parallel encls locatecl in the slots ancl surrouncling saicl pole pieces, the encls 0f said (30llS projecting beyoncl the encls 0f tl1e core, means f01 retaining saicl c0ils in the slots, anal 1gicl means surrouncling tl1e portions of the coils projecting beyoncl the core to protect und retain tl1e Same in position.

8. In a rotary fielcl member 0f a dynamoelectric machine, a shaft, a c0re comprising a definite number of rigid circula1 disks 1nountecl 011 the shaft, saicl disks lmving wedge-shapecl pole pieces, und coils of edgewisse-wouncl strap conclucting material surrounding the polepieces, t-he sides 0f tl1e coils being radial ancl the individual turns 0r layers of the encl portions of the coils lying in concentric cylinclrical surfaces.

9. 111 a rotary fielcl member of a dynamoelectric machine, a shaft, a core comprising a definite number 0f rigid circular disks mountecl 011 the shaft said clisks hzwing radial slots ancl wedge-slmpecl pole pieces ancl n plurality 03E coils of eclgewise-wound strap conclucting 1naterial surrounding euch pole pieca, the sicles 0I" the c0ils being radial ancl the'incliviclual turns 0f the encls 0f the coils being in concentrlc cylinclric-al surfaces.

In testimony whereof I alfix my signature, in the presence of (WO witnesses.

BEKNARD ARTHUR BEHREND Witnesses ARTHUR F. KWIS, IIARRIET SUTPHIN. 

